The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch an Earth observation satellite (EOS) equipped with dual-frequency synthetic aperture radar (SAR) in 2025. It will be the first radar imaging satellite to use dual frequencies. It will be used for remote sensing, to observe and understand natural processes on Earth. For example, its left-facing instruments will study the Antarcticcryosphere.[7] With a total cost estimated at US$1.5 billion, NISAR is likely to be the world's most expensive Earth-imaging satellite.[8]
The mission is a partnership between NASA and ISRO.[10] Under the terms of the agreement, NASA will provide the mission's L-bandsynthetic aperture radar (SAR), a high-rate telecommunication subsystem for scientific data GPS receivers, a solid-state recorder, and a payload data subsystem. ISRO will provide the satellite bus, an S-bandsynthetic aperture radar (SAR), the launch vehicle, and associated launch services.[12]
All data from NISAR will be freely available one to two days after observation and within hours in case of emergencies like natural disasters.[9] Data collected from NISAR will reveal information about the evolution and state of Earth's crust, help scientists better understand our planet's natural processes and changing climate, and aid future resource and hazard management.[10]
The satellite will be three-axis stabilized. It will use a 12m (39ft) deployable mesh antenna and will operate on both the L- and S- microwave bands.[10] The aperture mesh reflector (antenna) will be supplied by Astro Aerospace.[13] Weighing about 142 pounds (64 kilograms), the reflector features a cylindrical frame made of 123 composite struts and a gold-plated wire mesh and is the largest of its kind deployed in space.[14]
The National Centre of Geodesy facilities at IIT-Kanpur and IIT-Patna will host a corner reflector for NISAR.It will play a key role in calibration and course correction of the Nisar satellite's radar during the in-orbit checkout phase.[15]
ISRO's share of the project cost is about ₹788 crore (US$93million), and NASA's share is about US$1,118 million ($1.118 billion).[16][17][15]
Mission
Delays
The satellite was fully integrated in January 2024 and was performing its final testing and analysis in preparation for launch.[18] However, in an interview with the Times of India, Chairman of ISRO Sreedhara Panicker Somanath said that though the GSLV for NISAR will be built by March–April 2024, the satellite is still undergoing tests and they were expecting some delay.[19] Tests found that the large primary radar reflector might face higher-than-expected temperatures when stowed during flight and so it was returned to JPL, its manufacturer in California, to apply a reflective coating to mitigate the risk of overheating.[20][21] It was the first GSLV Mk II launch to Low Earth orbitand to SSPO
NISAR lifted off aboard an ISRO Geosynchronous Satellite Launch Vehicle rocket at 5:40p.m. IST on the 30th of July 2025. ISRO ground controllers in Bengaluru began communicating with NISAR about 18 minutes after launch, at just after 8:29a.m. EDT, and confirmed it is operating as expected. It was the GSLV rocket’s first mission to Sun-synchronous polar orbit.[26][27][28] The satellite will enter a 90-day Checkout phase and deploy its primary Radar reflector before beginning of its operational life.[29] The orbit will be a Sun-Synchronous Orbit (SSO), dawn-to-dusk type. The planned mission life is 5 years.[1]
Deployment and Commissioning
NISAR deployment stages
The deployment process for the spacecraft started on August 9, 2025 with the deployment of the 9 meter long booms first joint. The boom was fully deployed by August 13. 17 days after launch, on August 15, ISRO and NASA mission controllers fired small explosive bolts to unfurl the 12 meters wide drum-shaped primary radar reflector for NISAR.The whole bloom process took 37 minutes and was completed with the locking of cables and activation of motors to fix the reflectors final shape. It then proceeded to raise and circularise its 747km orbit on August 26.Pre-operational checks were then conducted by both NASA & ISRO teams to validate the health and readiness of all major systems, including the radar payload. Mission controllers anticipate they will start receiving science-quality radar images in September 2025. The spacecraft is expected to begin science operations by Fall 2025, or about 90 days after launch.[14][30][31][32]
NISAR captured its first SAR images using its L-SAR on August 23rd over North Dakota.[30]
Gallery
NISAR diagram
NISAR undergoing tests
NISAR solar array
NISAR's DGA antenna
NISAR being Integrated with the Payload Fairing of GSLV F16
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
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